In November of 2007 the World Cancer Research Fund published a massive study about the various types of risk factors for different types of cancer. A panel of 22 really eminent scientists from around the world examined over 7000 scientific papers, and they were really excited about their results, because they found that one third of cancers were due to risk factors that could be reduced.
In other words really good news, they said that by following some simple advice it should be possible to prevent about a third of all cancer. The response of much of the media in the UK was interesting and perhaps predictable – they were called ‘public health fascists’ and ‘health Nazi’s’ by some of the tabloid newspapers. Just because they were telling people how to avoid cancer.
This says something about how receptive we all are to health advice, but perhaps it also says something about how bad doctors and scientists can be at explaining things.
The report had quite a bit to say about alcohol and cancer and I will try and give you the key points.
Unfortunately drinking alcohol does increase your risk of certain types of cancer including: breast cancer, mouth, throat and gullet cancer, colon cancer and liver cancer - there is absolutely no doubt about this at all.
The risk of cancer starts at low levels of alcohol intake, and increases in a straight line. Of these risks perhaps the most important is breast cancer which is very common, around 10% of all women will get breast cancer, so a 10% increase in risk will result in 1 in every 100 women getting breast cancer as a result. Drinking 14 units of alcohol (1.5 bottles of wine) a week over a prolonged time will increase the risk of breast cancer by 10-20% , and thus 1 or 2 in every 100 women drinking at this level may develop breast cancer as a result.
There are two ways of looking at this:
If you really enjoy those glasses of wine, then you may say to yourself that a 1:100 chance that it will induce breast cancer is worth it.
On the other hand if all women drank at that level that 1 in 100 risk would mean an extra 4000 women getting breast cancer each year – so you can see why the public health doctors are concerned.
By the time you are drinking 60-70 units a week (7-8 bottles of wine) the risk of breast cancer doubles, and 1 in every 10 women will get breast cancer as a result.
Both men and women who drink are also at increased risk of cancer of the mouth, larynx and gullet. The relative risks for each are slightly higher but as these cancers are less common the absolute risks are reduced.
For colon cancer the risk is smaller, but as this cancer is extremely common, alcohol related colon cancer is a significant problem.
On the other hand although mouth cancer is relatively uncommon, the relative risk for a heavy drinking heavy smoker increases by 40 times - so most of the 5000 mouth cancers seen by dentists each year are in this risk group, and it is a particularly nasty cancer to get.
For all of these cancers the risk of cancer is directly proportional to the amount of alcohol that you drink – the more you drink the higher the risk.
If you would like to reduce your overall lifetime risk of getting cancer by about a third, then don’t smoke, don’t drink any alcohol, don’t get fat, take lots of physical exercise, avoid sugary foods, eat five portions of vegetables a day and less than 500g of red meat a week, avoid salty or processed foods (ie bacon) and nutritional supplements. It also makes a difference if you were breastfed as a child, and perhaps surprisingly are not too tall.
If on the other hand you are a tall, overweight, wine drinking, cigar smoking, beef eating slob who eats bacon sandwiches and rides a fast motorbike, then you are statistically less likely to live to a ripe old age.